Exemplary sigma-delta (or: delta-sigma) analog to digital converters (SD-ADCs) are often employed to continuously capture measuring data. As the SD-ADC measuring process involves integration of a plurality of samples over a time window of a certain length, the sigma-delta (SD) method does not allow direct generation of a measuring value which corresponds to one certain point in time, but to a certain measurement time window. In order to establish a timing relation between these measurement windows and other tasks in the system, the generated data is supplied with a corresponding time stamp indicating the generation time of the respective value and each value is stored together with its corresponding time stamp. To extend a value generation over larger measurement windows, an additional integrator can be used to integrate over a defined number of decimation results, wherein a decimation result is a result of a respective measurement window.
If a measuring value is required at a certain point within a time window between two SD-ADC values generated subsequently, the required value may be calculated by linear interpolating or extrapolating two SD-ADC values generated subsequently. For this purpose, the time at which a value is required has to be captured and stored so that it can be related to the points of time at which the two “nearest” SD-ADC values have been generated. For example, if measuring values are required periodically and the time periods of these required values are shorter than the time periods of the generated SD-ADC values, calculation of “in-between” or intermediate values is continuously required.
This, however, requires specially adapted hardware and respective connections in the system so that, in general, custom-made modules have to be used instead of generic modules. In particular, three direct memory access (DMA) channels are required for moving data from different modules to memory (ADC value and two timer values), wherein each DMA channel takes a large amount of chip area and, thus, is very costly.
Therefore, among other needs, there exists a need for a system for providing SD-ADC values and timer values required for calculating intermediate SD-ADC values which takes a reduced amount of chip area without involving significant loss of accuracy and/or resolution.